Rapid Determination Of Nitrate Nitrogen And Nitrite Nitrogen By Second Derivative Spectrophotometry

Water is the source of human life.However,the water resources of our country are not only extremely scarce,but also because of the rapid and efficient development of the economy,the problem of water pollution is becoming more and more serious.The nitrogen content index in water quality monitoring is a very important one.Part of the nitrogen content is derived from nitrate nitrogen and nitrite nitrogen.Therefore,a rapid and effective measurement method is very important for the determination of total nitrogen in water.And It has great significance to protect water resources.There are many methods for the determination of nitrate nitrogen and nitrite nitrogen.But many of them need to separate the sample,and the way of separation is complicated.And the determination process will use a large number of chemical reagents,and it is likely to cause secondary pollution to the environment.Other methods require higher equipment costs,and they are not easy to popularize.Based on the above situation,the work of this paper includes the following parts:First,briefly introduces the origin and harm of nitrate and nitrite nitrogen nitrate,and existing determination methods of the two are described and analyzed.The work done by researchers at home and abroad on the determination of nitrate nitrogen and nitrite nitrogen in these years is also introduced.The principles and related knowledge of UV and derivative spectrometry used in this paper are emphatically introduced.Secondly,we have prepared a standard solution of nitrate nitrogen and nitrite nitrogen.And We study the two order derivative spectra of the standard solution of the single component and the mixed component by ultraviolet spectrophotometry and the second derivative spectrophotometry.The determination wavelength of the two in the mixed component is determined.The standard curves and regression equations are determined at the corresponding wavelengths.The water samples from the three rivers of the Tang River and New River in Qinhuangdao have been tested by this method for the determination of nitrate nitrogen and nitrite nitrogen.The result analysis proves the feasibility of the method proposed in this paper.Finaly,the influence of turbidity,acidity,alkalinity,some coexisting ions and so forth on the determination of nitrate nitrogen and nitrite nitrogen are also studied in this paper.The most suitable testing conditions are given to make the result more accurate.